Hi Lexus Brothers!

There is a 2008 RX400h, 78,000km, and when ICE is hot, and suddenly (hit) the engine starts up. No error code, all right in addition. Since I've got the car I'm curious about this, because it's when ICE starts so gently that I do not even notice it. At higher speeds, you can not feel the ICE turn on, just when I'm out of standby. Is this normal? Thanks!

I'm sorry for the weak English, I'm writing from Hungary

 

Are you describing the V6 engine starting suddenly when driving slowly or parked?
Your RX400h uses the large hybrid battery to run the Air Conditioner as well as
powering the entire car down the road. It is normal for the engine to stay off for as
long as possible and then start when the battery runs down. It sounds and feels
rough and loud compared to the nearly silent operation that you were enjoying.

Try putting the hybrid system screen on the dash and watch the battery indicator.
Use the dash button "Info" and then "Trip Info / Energy" Does the battery scale
go down to 2 or 3 bars and then the IC engine start up? This would be normal.

 

I've driven (new) electric hybrid cars and have experienced the same thing. Sometimes, the ICE is off and abruptly starts up again when I am stopped or when I am coasting at low speeds.

I think this is normal for hybrid cars because the ICE engine is needed to power the vehicle hydraulics and recharge the batteries while driving, even if the car is running on electric motors.

Also, the ICE needs to be warm to function most efficiently, hence, the vehicle turns on the ICE in order to warm up the engine and recirculate oil and fluids through the powertrain components.

 

Thanks for the help, but I do not have the problem of switching on the ICE but switching on. But it's coming up hard and suddenly. I feel the "hit" when it comes on and it's bothering me. Because sometimes it switches silently off at startup, sometimes hard. Anything else?

THX!

 

I am afraid, you'll have to get used to this. Also, I understand English is not your primary language, but it is still hard to understand what you are referring to.
let me try:
When engine and all systems are well warmed up, sometimes engine starts on nice and smooth and sometimes there is a jerk that you can feel? Is this correct description of your concern?
This is why I said - get used to it. They do so. Especially winter time, when it is cold outside. Engine is the only heat source, so when it is cold, computer forces engine to run more often, even after initial warm up, to produce heat. My 3.5L V6 hybrid does this and I got used to it. Nothing you can do about it. On hybrids, they modified engine into a pseudo-Atkinson cycle behavior. As engine it turned on by motor generator, not by starter, when engine shuts down, it is intended to stop just past the top dead center, so it is easier for motor to start it. Likely, it does not always stop exactly where it is intended to, so start up is a bit jerky.
Another issue, and it is my personal opinion, is that that engine produces a lot of torque but has very weak torque absorbing mounts. Front and side engine mounts are very thick and strong. But, ones that are supposed to absorb engine toque along the vehicle long axis are rather weak. Front engine mount has some to do with this. Then you have upper torque mount, dog bone and, at the bottom of the engine, on passenger side, there is torque mount. That one is about the most silly torque mount I have seen.
I had all of them replaced on my V6 hybrid, at 93 000 miles, and they were all in various stages of degradation. I am still scratching my head trying to even understand, what the heck that lower torque mount is supposed to do. I am also considering adding shock dampener to this engine, as last resort, as jerk is very annoying.